Take a deep breath…why bother?

Why is it that, when, in the heat of the moment, you find yourself wound up, or feeling very stressed, the one thing that can make a difference is to take a few deep breaths? Is there any science to support this advice?

Contrary to popular belief, the heart does not beat like a metronome; it is far more chaotic. In fact the gap between each heartbeat varies, and, somewhat counter intuitively, this is a good thing. The more variation, the better (mostly).

One of the drivers of this variation is what happens when you breathe. As you inhale, the activity of the nerve to your heart is inhibited and this results in your heart rate increasing. As you breathe out this inhibition ceases and your heart rate falls. On average, when at rest, you breathe in and out between 12 and 18 times per minute.

Another driver of the variation in your heart rate is the activity of blood pressure receptors in your blood vessels. These respond to the increase in blood pressure that results from your heart contracting as it sends the blood around the body and relaxing between beats, sending signals for your heart rate to slow down. As the pressure decreases following the heartbeat, they send a signal to increase heart rate. In this way, the body is able to maintain blood pressure at the right level. This response to changes in blood pressure happens every 4 or 5 seconds. The consequence of the impact of breathing and these pressure receptors in the bloodstream results in the variation in the time between heartbeats. It is this variation that is known as heart rate variability (HRV).

You may recall that when you are threatened it results in a ‘fight or flight’ response, i.e. you start feeling stressed. An increase in HRV results the opposite of the ‘flight or fight’ response and you start to feel more relaxed. The key point here is that by increasing your HRV you can change your state to become more relaxed and feel more in control. You may be interested to know that many smart watches these days will measure your HRV, and it is often a core element in how such devices determine your current levels of stress.

How do we increase HRV? The answer is to breathe deeply. When you breathe at about 6 breaths a minute the impact on your HRV is profound. It results in much larger variations in HRV than when breathing ‘normally’. The greater your HRV, the more relaxed you will feel.

Why 6 breaths? If you are a small person or a child it may be more like 7 and if you are very tall, it may be more like 5 breaths, but for most of us 6 breaths is what works best. This breathing rate produces the greatest increase in HRV. Research has also demonstrated that slow breathing at six breaths per minute has a positive effect on asthma, affective mood disorder, and pain.

We have recently studied changes in brain activity associated with completion of a task that creates mental workload. One group of participants was asked to breathe at 6 breaths per minute after the completion of the mental workload task, whilst the other group breathed normally. The impact was dramatic. The people asked to breathe at 6 breaths per minute recovered much much faster from the mental workload task than did the ‘normal’ breathing  group. In fact, the impact of slower breathing was almost instantaneous.

The joy of taking a few deep breaths is free, easy to do, requires no special kit and needs very little training. You can download an app if you want help pacing yourself. Alternatively, count to five slowly in your head as you breathe in, then count to 5 in your head as you breathe out. We recommend 5 minutes for the best effect, but, frankly, even 30 seconds will help.

And in case you are in any doubt as to the value of paced breathing at 6 breaths per minute, there is evidence to suggest that slow paced breathing is more effective than mindfulness for restoring you to a more ‘in-control’ state.

Dr Dominic Irvine and Professor Emeritus Simon Jobson